Secure AF Relaying in Power-Constrained UAV Networks

This paper proposes a secure amplify-and-forward (AF) relaying scheme in unmanned aerial vehicle (UAV) networks while accounting for the power consumption limitations of UAVs. Since a UAV's battery life is limited, we propose selecting the UAV relays based on their probability of availability, which we model to be a function of the UAV's power consumption model. Then, physical layer security is achieved by partitioning the limited available relays into information relaying UAVs and cooperative jammers while aiming to maximize the secrecy rate of the network when an eavesdropper is located in the vicinity of the destination node. Meanwhile, the information bearing relays use beamforming to enhance the information delivery to the destination, and the cooperative jamming relays use precoded artificial-noise scheme to degrade the eavesdropping links' received signal-to-noise ratios. Simulation results show significant secrecy rate enhancements when the proposed schemes are adopted compared to conventional relaying scenarios, especially when cooperative jamming is deployed.